Current CPUs with modern energy-saving features can cause bandwidth limitations on USB. This is a direct consequence of CPU cores falling into so-called sleep states. CPU cores enter these sleep states independently from the load level on the USB. This can lead to the following malfunctions:
- Low USB bandwidth provided by the PC system
- TransferFailed errors occurring even at moderate pixel clock settings
- Camera operates at low speed only
- Black images receiving
To fight the low USB bandwidth provided by the PC system:
- Please remove other USB devices from the system (USB keyboard and mouse are fine). Run tests with only one device connected at once.
- Make sure to use a USB port directly on the mainboard. Front panel or other ports are connected to the mainboard with poor cabling quality frequently.
- Make sure to use USB2.0 certified cables to connect the device.
- If you are using USB hubs or extensions: Run a test without these devices, connect the device directly to the PC.
- Disable other equipment that is connected via USB. For example, WLAN and Bluetooth adapters might use a USB to connect.
- If you are using a mobile PC: run it on main power, not the battery.
- Check your energy-saving options in the operating system. Disable energy-saving features and set the available features to “full performance” or similarly named options.
- If you checked the above and still observe low USB performance you might be experiencing the issue with CPU sleep states (Windows 10).
To fight the 'sleep' states:
- Download CPUDISABLE C2 C3.reg file by following this link
- Run CPUDISABLE C2 C3.reg (by running this file the C3 condition will be disabled in the Windows registry)
- Reboot your PC